Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/trees/layer_tree.h

Index: cc/trees/layer_tree.h
diff --git a/cc/trees/layer_tree.h b/cc/trees/layer_tree.h
index bb7e3d2adbf9af2cae7c996edfa1617bc75cf454..10044dd03f1c6698ebd2d49b9956698fea4e8636 100644
--- a/cc/trees/layer_tree.h
+++ b/cc/trees/layer_tree.h
@@ -10,6 +10,7 @@
 
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
+#include "cc/trees/mutator_host_client.h"
 
 namespace cc {
 
@@ -20,13 +21,15 @@ class LayerUpdate;
 
 class AnimationHost;
 class Layer;
+class LayerTreeHost;
 
-class CC_EXPORT LayerTree {
+class CC_EXPORT LayerTree : public MutatorHostClient {
  public:
   using LayerSet = std::unordered_set<Layer*>;
   using LayerIdMap = std::unordered_map<int, Layer*>;
 
-  explicit LayerTree(std::unique_ptr<AnimationHost> animation_host);
+  LayerTree(std::unique_ptr<AnimationHost> animation_host,
+            LayerTreeHost* layer_tree_host);
   ~LayerTree();
 
   void RegisterLayer(Layer* layer);
@@ -47,6 +50,44 @@ class CC_EXPORT LayerTree {
 
   bool in_paint_layer_contents() const { return in_paint_layer_contents_; }
 
+  Layer* LayerByElementId(ElementId element_id) const;
+  void AddToElementMap(Layer* layer);
+  void RemoveFromElementMap(Layer* layer);
+
+  // MutatorHostClient implementation.
+  bool IsElementInList(ElementId element_id,
+                       ElementListType list_type) const override;
+  void SetMutatorsNeedCommit() override;
+  void SetMutatorsNeedRebuildPropertyTrees() override;
+  void SetElementFilterMutated(ElementId element_id,
+                               ElementListType list_type,
+                               const FilterOperations& filters) override;
+  void SetElementOpacityMutated(ElementId element_id,
+                                ElementListType list_type,
+                                float opacity) override;
+  void SetElementTransformMutated(ElementId element_id,
+                                  ElementListType list_type,
+                                  const gfx::Transform& transform) override;
+  void SetElementScrollOffsetMutated(
+      ElementId element_id,
+      ElementListType list_type,
+      const gfx::ScrollOffset& scroll_offset) override;
+  void ElementTransformIsAnimatingChanged(ElementId element_id,
+                                          ElementListType list_type,
+                                          AnimationChangeType change_type,
+                                          bool is_animating) override;
+  void ElementOpacityIsAnimatingChanged(ElementId element_id,
+                                        ElementListType list_type,
+                                        AnimationChangeType change_type,
+                                        bool is_animating) override;
+  void ElementFilterIsAnimatingChanged(ElementId element_id,
+                                       ElementListType list_type,
+                                       AnimationChangeType change_type,
+                                       bool is_animating) override;
+  void ScrollOffsetAnimationFinished() override {}
+  gfx::ScrollOffset GetScrollOffsetForAnimation(
+      ElementId element_id) const override;
+
  private:
   friend class LayerTreeHostSerializationTest;
 
@@ -56,9 +97,13 @@ class CC_EXPORT LayerTree {
   // Layer id to Layer map.
   LayerIdMap layer_id_map_;
 
+  using ElementLayersMap = std::unordered_map<ElementId, Layer*, ElementIdHash>;
+  ElementLayersMap element_layers_map_;
+
   bool in_paint_layer_contents_;
 
   std::unique_ptr<AnimationHost> animation_host_;
+  LayerTreeHost* layer_tree_host_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTree);
 };